WJNS  Vol.4 No.4 , August 2014
Evolution and Role of Intraoperative Neurophysiological Monitoring in Intramedullary Spinal Cord Surgery: A 2-Year Series from Saudi Arabia

Introduction: Despite recent advances in neuroimaging and microsurgical techniques, surgical resection of spinal cord tumours remains a challenge. However, the evolution with advances and refinement of neurophysiological equipment and methodologies, intra-operative neurophysiolo- gical monitoring (IONM) is now regarded as an essential adjunct to the surgical management of intramedullary spinal cord tumours. This study aims to report our preliminary experience with IONM and emphasise its effective role of achieving maximum tumour resection and minimising neurological injury. Methods: This is a retrospective study performed at our institution between July 2012 and August 2013. It included a cohort of 6 consecutive patients presented with intramedullary spinal cord tumours. Their mean age was 26 years (range, 4 months - 37 years), all were males, and the mean follow up was 11.6 months. Results: We combined the use of somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) in spinal cord surgery. SSEPs are monitored during the incision of the dorsal midline of the spinal cord and this was used in two of our patients and MEPs were used as an essential monitoring during the tumour resection. In addition, we used free-running electromyography (EMG) and muscle MEPs (mMEPs) during tumour resection. Four of our patients (two with ependymoma, one with ganglioglioma, and one with pilocytic astrocytoma) had complete tumour resection and two patients (pilocytic and diffuse astrocytoma) had IONM changes during surgery and had partial tumour resection. At 6-month follow up all our patients had made a good recovery with no new neurological sequelae. Conclusion: This small series and literature review is presented to add and improve the understanding of IONM in intramedullary spinal cord procedures and to reinforce the importance of IONM in optimising tumour resection and neurological outcome. Our series confirm that without D-wave monitoring, free-running EMG and MEP monitoring during tumour resection remain an important adjunct. We also draw attention to the fact that changes in the free-running EMG occur before any changes in the MEPs are noted.


Cite this paper
Baeesa, S. , Labram, E. , Mahfoodh, M. , Khalid, M. and Al-Said, Y. (2014) Evolution and Role of Intraoperative Neurophysiological Monitoring in Intramedullary Spinal Cord Surgery: A 2-Year Series from Saudi Arabia. World Journal of Neuroscience, 4, 326-333. doi: 10.4236/wjns.2014.44037.
[1]   Brotchi, J. (2002) Intrinsic Spinal Cord Tumour Resection. Neurosurgery, 50, 1059-1063.

[2]   Jellinek, D., Jewkes, D. and Symon, L. (1991) Non-Invasive Intraoperative Monitoring of Motor Evoked Potentials under Propofol Anaesthesia: Effect of Spinal Surgery on the Amplitude and Latency of Motor Evoked Potentials. Neurosurgery, 29, 551-557. http://dx.doi.org/10.1227/00006123-199110000-00011

[3]   Quinones-Hinojosa, A., Lyon, R., Gulati, M., Gupta, N. and Yingling, C. (2002) Spinal Cord Mapping as an Adjunct for Resection of Intramedullary Spinal Cord Tumors. Neurosurgery, 51, 1199-1206.

[4]   Kothbauer, K.F., Deletis, V. and Epstein, F.J. (1997) Intraoperative Spinal Cord Monitoring for Intramedullary Surgery: An Essential Adjunct. Pediatric Neurosurgery, 26, 247-254.

[5]   Elsberg, C.A. and Beer, E. (1911) The Operability of Intramedullary Tumors of the Spinal Cord: A Report of Two Operations with Remarks upon the Extrusion of Inraspinal Tumours. The American Journal of the Medical Sciences, 142, 636-647. http://dx.doi.org/10.1097/00000441-191111000-00002

[6]   Constantini, S., Miller, D.C., Allen, J.C., Rorke, L.B., Freed, D. and Epstein, F.J. (2000) Radical Excision of Intramedullary Spinal Cord Tumors: Surgical Morbidity and Long-Term Follow-Up Evaluation in 164 Children and Young Adults. Journal of Neurosurgery, 93, 183-193.

[7]   Epstein, F.J., Farmer, J.-P. and Freed, D. (1993) Adult Intramedullary Spinal Cord Ependymoma: The Results of Surgery in 38 Patients. Journal of Neurosurgery, 79, 204-209.

[8]   Raco, A., Esposito, V., Lenzi, J., Piccirilli, M., Delfini, R. and Cantore, G. (2005) Long-Term Follow-Up of Intramedullary Spinal Cord Tumors: A Series of 202 Cases. Neurosurgery, 56, 972-981.

[9]   Deletis, V. and Sala, F. (2008) Intraoperative Neurophysiological Monitoring of the Spinal Cord during Spinal Cord and Spine Surgery: A Review Focus on the Corticospinal Tracts. Clinical Neurophysiology, 119, 248-264.

[10]   Pearce, J.M. (2001) Emil Heinrich Du Bois-Reymond (1818-1896). Journal of Neurology, Neurosurgery Psychiatry, 71, 620. http://dx.doi.org/10.1136/jnnp.71.5.620

[11]   Dawson, G.D. (1950) Cerebral Responses to Nerve Stimulation in Man. British Medical Bulletin, 6, 326-329.

[12]   Tamaki, T. and Kubota, S. (2007) History of the Development of Intraoperative Spinal Cord Monitoring. European Spine Journal, 16, 140-146. http://dx.doi.org/10.1007/s00586-007-0416-9

[13]   Burke, D., Hicks, R., Stephen, J., Woodforth, I. and Crawford, M. (1992) Assessment of Corticospinal and Somatosensory Conduction Simultaneously during Scoliosis Surgery. Electroencephalography and Clinical Neurophysiology, 85, 388-396. http://dx.doi.org/10.1016/0168-5597(92)90052-D

[14]   Morota, N., Deletis, V., Constantini, S., Kofler, M., Cohen, H. and Epstein, F.J. (1997) The Role of Motor Evoked Potentials during Surgery for Intramedullary Spinal Cord Tumors. Neurosurgery, 41, 1327-1336.

[15]   Owen, J.H. (1999) The Application of Intraoperative Monitoring during Surgery for Spinal Deformity. Spine, 24, 2649-2662. http://dx.doi.org/10.1097/00007632-199912150-00012

[16]   Pelosi, L., Lamb, J., Grevitt, M., Mehdian, S., Webb, J. and Blumhardt, L. (2002) Combined Monitoring of Motor and Somatosensory Evoked Potentials in Orthopaedic Spinal Surgery. Clinical Neurophysiology, 113, 1082-1091.

[17]   Merton, P.A. and Morton, H.B. (1980) Stimulation of the Cerebral Cortex in the Intact Human Subject. Nature, 285, 227. http://dx.doi.org/10.1038/285227a0

[18]   Skinner, S., Nagib, M., Bergman, T., Maxwell, R. and Msangi, G. (2005) The Initial Use of Free-Running Electromyography to Detect Early Motor Tract Injury during Resection of Intramedullary Spinal Cord Lesions. Neurosurgery, 56, 299-314. http://dx.doi.org/10.1227/01.NEU.0000156545.33814.8D

[19]   Wiedemayer, H., Fauser, B., Sandalcioglu, I.E., Schafer, H. and Stolke, D. (2002) The Impact of Neurophysiological Intraoperative Monitoring on Surgical Decisions: A Critical Analysis of 423 Cases. Journal of Neurosurgery, 96, 255-262. http://dx.doi.org/10.3171/jns.2002.96.2.0255

[20]   Lesser, R.P., Raudzens, P., Luders, H., Nuwer, M.R., Goldie, W.D., Morris, H.H., Dinner, D.S., Klem, G., Hahn, J.F., Shetter, A.G., Ginsburg, H.H. and Gurd, A.R. (1986) Postoperative Neurological Deficits May Occur Despite Unchanged Intraoperative Somatosensory Evoked Potentials. Annals of Neurology, 19, 22-25.

[21]   Kearse Jr., L.A., Lopez-Bresnahan, M., McPeck, K. and Tambe, V. (1993) Loss of Somatosensory Evoked Potentials during Intramedullary Spinal Cord Surgery Predicts Postoperative Neurologic Deficits in Motor Function. Journal of Clinical Anesthesia, 5, 392-398. http://dx.doi.org/10.1016/0952-8180(93)90103-L

[22]   Deletis, V. (2002) Intraoperative Neurophysiology and Methodologies Used to Monitor the Functional Integrity of the Motor System: Neurophysiology in Neurosurgery: A Modern Intraoperative Approach. Academic, San Diego, 25-51.

[23]   Taniguchi, M., Nadstawek, J., Langenbach, U., Bremer, F. and Schramm, J. (1993) Effects of Four Intravenous Anesthetic Agents on Motor Evoked Potentials Elicited by Magnetic Transcranial Stimulation. Neurosurgery, 33, 407-415.

[24]   Calancie, B., Harris, W., Brindle, G.F., Green, B.A. and Landy, H.J. (2001) Threshold-Level Repetitive Transcranial Electrical Stimulation for Intraoperative Monitoring of Central Motor Conduction. Journal of Neurosurgery, 95, 161-168. http://dx.doi.org/10.3171/spi.2001.95.2.0161

[25]   Macdonald, D.B. (2006) Intraoperative Motor Evoked Potential Monitoring: Overview and Update. Journal of Clinical Monitoring and Computing, 20, 347-377. http://dx.doi.org/10.1007/s10877-006-9033-0

[26]   Sala, F., Bricolo, A., Faccioli, F., Lanteri, P. and Gerosa, M. (2007) Surgery for Intramedullary Spinal Cord Tumors: the Role of Intraoperative (Neurophysiological) Monitoring. European Spine Journal, 16, S130-S139.

[27]   Kothbauer, K.F., Deletis, V. and Epstein, F.J. (1998) Motor-Evoked Potential Monitoring for Intramedullary Spinal Cord Tumor Surgery: Correlation of Clinical and Neurophysiological Data in a Series of 100 Consecutive Procedures. Neurosurgical Focus, 4, e1.

[28]   Quinones-Hinojosa, A., Lyon, R., Zada, G., Lamborn, K.R., Gupta, N., Parsa, A.T., McDermott, M.W. and Weinstein, P.R. (2005) Changes in Transcranial Motor Evoked Potentials during Intramedullary Spinal Cord Tumor Resection Correlate with Postoperative Motor Function. Neurosurgery, 56, 982-993.

[29]   Sala, F., Palandri, G., Basso, E., Lanteri, P., Deletis, V., Faccioli, F. and Bricolo, A. (2006) Motor Evoked Potential Monitoring Improves Outcome after Surgery for Intramedullary Spinal Cord Tumors: A Historical Control Study. Neurosurgery, 58, 1129-1143. http://dx.doi.org/10.1227/01.NEU.0000215948.97195.58

[30]   Calancie, B. and Molano, M.R. (2008) Alarm Criteria for Motor-Evoked Potentials: What’s Wrong with the “Presence-or-Absence” Approach? Spine, 33, 406-414. http://dx.doi.org/10.1097/BRS.0b013e3181642a2f

[31]   Pajewski, T.N., Arlet, V. and Phillips, L.H. (2007) Current Approach on Spinal Cord Monitoring: The Point of View of the Neurologist, the Anesthesiologist and the Spine Surgeon. European Spine Journal, 16, 115-129.